attachment_render_state.go RawHistoryFolder

1package daemon
2
3// attachmentRenderState is one attachment's composition state: what the last
4// emitted frame looked like and the per-pane captures it was built from. The
5// paint transaction owns it through attachedClient.sendMu; every other path
6// changes it only through the transitions below, so the rules for when a
7// composition or a pane snapshot may be reused live in one place.
8type attachmentRenderState struct {
9	// cache is the last successfully emitted composition. spare is its
10	// alternate buffer; the two must never share mutable backing storage.
11	cache composeCacheInput
12	spare composeCacheInput
13	// capture is reusable scratch for one capture pass.
14	capture renderCaptureScratch
15	// panes is keyed by pane ownership, not the tab-local PaneID, so snapshots
16	// cannot leak when an attachment switches tabs or sessions.
17	panes map[*pane]capturedPaneRenderState
18}
19
20// commitComposition records a successfully emitted composition and recycles
21// the previous one as the next spare buffer.
22func (r *attachmentRenderState) commitComposition(composed composeCacheInput) {
23	r.spare = r.cache
24	r.cache = composed
25}
26
27// forgetComposition forces the next frame to be composed from scratch.
28func (r *attachmentRenderState) forgetComposition() {
29	r.cache = composeCacheInput{}
30	r.spare = composeCacheInput{}
31}
32
33// forgetAllPanes drops every pane capture snapshot.
34func (r *attachmentRenderState) forgetAllPanes() { r.panes = nil }
35
36// forgetPanes drops the capture snapshots of panes that left this attachment.
37func (r *attachmentRenderState) forgetPanes(panes ...*pane) {
38	for _, p := range panes {
39		delete(r.panes, p)
40	}
41}
42
43// paneSnapshot returns the previous capture of p, if any.
44func (r *attachmentRenderState) paneSnapshot(p *pane) capturedPaneRenderState {
45	return r.panes[p]
46}
47
48// storePaneSnapshot retains the latest capture of p for the next pass.
49func (r *attachmentRenderState) storePaneSnapshot(p *pane, captured capturedPaneRenderState) {
50	if r.panes == nil {
51		r.panes = make(map[*pane]capturedPaneRenderState)
52	}
53	r.panes[p] = captured
54}